/*
 * @(#)OSXAdapter.java
 *
 * Copyright (c) 2009-2010 by the original authors of JHotDraw and all its
 * contributors. All rights reserved.
 *
 * You may not use, copy or modify this file, except in compliance with the
 * license agreement you entered into with the copyright holders. For details
 * see accompanying license terms.
 *
 * This class has been derived from class OSXAdapter 2.0 by Apple Inc.
 * http://developer.apple.com/mac/library/samplecode/OSXAdapter/listing3.html
 *
 * Original disclaimer:
 *
 * File: OSXAdapter.java
 *
 * Abstract: Hooks existing preferences/about/quit functionality from an
 * existing Java app into handlers for the Mac OS X application menu.
 * Uses a Proxy object to dynamically implement the
 * com.apple.eawt.ApplicationListener interface and register it with the
 * com.apple.eawt.Application object.  This allows the complete project
 * to be both built and run on any platform without any stubs or
 * placeholders. Useful for developers looking to implement Mac OS X
 * features while supporting multiple platforms with minimal impact.
 *
 * Version: 2.0
 *
 * Disclaimer: IMPORTANT:  This Apple software is supplied to you by
 * Apple Inc. ("Apple") in consideration of your agreement to the
 * following terms, and your use, installation, modification or
 * redistribution of this Apple software constitutes acceptance of these
 * terms.  If you do not agree with these terms, please do not use,
 * install, modify or redistribute this Apple software.
 *
 * In consideration of your agreement to abide by the following terms, and
 * subject to these terms, Apple grants you a personal, non-exclusive
 * license, under Apple's copyrights in this original Apple software (the
 * "Apple Software"), to use, reproduce, modify and redistribute the Apple
 * Software, with or without modifications, in source and/or binary forms;
 * provided that if you redistribute the Apple Software in its entirety and
 * without modifications, you must retain this notice and the following
 * text and disclaimers in all such redistributions of the Apple Software.
 * Neither the name, trademarks, service marks or logos of Apple Inc.
 * may be used to endorse or promote products derived from the Apple
 * Software without specific prior written permission from Apple.  Except
 * as expressly stated in this notice, no other rights or licenses, express
 * or implied, are granted by Apple herein, including but not limited to
 * any patent rights that may be infringed by your derivative works or by
 * other works in which the Apple Software may be incorporated.
 *
 * The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
 * MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
 * THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
 * OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
 *
 * IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
 * MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
 * AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
 * STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright © 2003-2007 Apple, Inc., All Rights Reserved
 */
package org.jhotdraw.app.osx;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.*;

/**
 * {@code OSXAdapter} uses a Proxy object to dynamically implement the
 * {@code com.apple.eawt.ApplicationListener} interface and register it with the
 * {@code com.apple.eawt.Application object}.  This allows the complete project
 * to be both built and run on any platform without any stubs or
 * placeholders. Useful for developers looking to implement Mac OS X
 * features while supporting multiple platforms with minimal impact.
 * <p>
 * This class has been derived from <a
 * href="http://developer.apple.com/mac/library/samplecode/OSXAdapter/listing3.html"
 * >OSXAdapter 2.0 © Apple Inc., All Rights Rserved</a>.
 *
 * @author Werner Randelshofer
 * @version $Id: OSXAdapter.java 717 2010-11-21 12:30:57Z rawcoder $
 */
public class OSXAdapter implements InvocationHandler {

    protected ActionListener targetAction;
    protected Object targetObject;
    protected Method targetMethod;
    protected String proxySignature;
    static Object macOSXApplication;

    /**
     * The action listener will be called when the application receives an Open
     * Application event from the Finder or another application. Usually this
     * will come from the Finder when a user double-clicks your application
     * icon. If there is any special code that you want to run when you user
     * launches your application from the Finder or by sending an Open
     * Application event from another application, include that code as part of
     * this handler. The Open Application event is sent after AWT has been loaded.
     */
    public static void setOpenApplicationHandler(ActionListener openHandler) {
        setHandler(new OSXAdapter("handleOpenApplication", openHandler));
    }
    /**
     * Called when the application receives a Reopen Application event from the
     * Finder or another application. Usually this will come when a user clicks
     * on your application icon in the Dock. If there is any special code that
     * needs to run when your user clicks on your application icon in the Dock
     * or when a Reopen Application event is sent from another application,
     * include that code as part of this handler.
     */
    public static void setReOpenApplicationHandler(ActionListener reopenHandler) {
        setHandler(new OSXAdapter("handleReOpenApplication", reopenHandler));
    }
    /**
     * The action listener will be called when the Quit menu item is selected
     * from the application menu.
     */
    public static void setQuitHandler(ActionListener aboutHandler) {
        setHandler(new OSXAdapter("handleQuit", aboutHandler) {

            // Override OSXAdapter.callTarget to always return false.
            @Override
            public boolean callTarget(Object appleEvent)  throws InvocationTargetException, IllegalAccessException {
                super.callTarget(appleEvent);
                return false;
            }
        });
    }

    /**
     * The action listener will be called when the user selects the About item
     * in the application menu.
     */
    public static void setAboutHandler(ActionListener aboutHandler) {
        boolean enableAboutMenu = (aboutHandler != null);
        if (enableAboutMenu) {
            setHandler(new OSXAdapter("handleAbout", aboutHandler));
        }
        // If we're setting a handler, enable the About menu item by calling
        // com.apple.eawt.Application reflectively
        try {
            Method enableAboutMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledAboutMenu", new Class[]{boolean.class});
            enableAboutMethod.invoke(macOSXApplication, new Object[]{Boolean.valueOf(enableAboutMenu)});
        } catch (Exception ex) {
            System.err.println("OSXAdapter could not access the About Menu");
            ex.printStackTrace();
        }
    }

    /**
     * Pass this method an {@code ActionListener} equipped to
     * display application options.
     * They will be called when the Preferences menu item is selected from the
     * application menu.
     */
    public static void setPreferencesHandler(ActionListener prefsHandler) {
        boolean enablePrefsMenu = (prefsHandler != null);
        if (enablePrefsMenu) {
            setHandler(new OSXAdapter("handlePreferences", prefsHandler));
        }
        // If we're setting a handler, enable the Preferences menu item by calling
        // com.apple.eawt.Application reflectively
        try {
            Method enablePrefsMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledPreferencesMenu", new Class[]{boolean.class});
            enablePrefsMethod.invoke(macOSXApplication, new Object[]{Boolean.valueOf(enablePrefsMenu)});
        } catch (Exception ex) {
            System.err.println("OSXAdapter could not access the Preferences Menu");
            ex.printStackTrace();
        }
    }

    /**
     * Pass this method an {@code ActionListener} equipped to
     * handle document events from the Finder.
     * Documents are registered with the Finder via the
     * CFBundleDocumentTypes dictionary in the application bundle's Info.plist.
     * <p>
     * The filename is passed as the {@code actionCommand}.
     */
    public static void setOpenFileHandler(ActionListener fileHandler) {
        setHandler(new OSXAdapter("handleOpenFile", fileHandler) {
            // Override OSXAdapter.callTarget to send information on the
            // file to be opened

            @Override
            public boolean callTarget(Object appleEvent) {
                if (appleEvent != null) {
                    try {
                        Method getFilenameMethod = appleEvent.getClass().getDeclaredMethod("getFilename", (Class[]) null);
                        String filename = (String) getFilenameMethod.invoke(appleEvent, (Object[]) null);
                        targetAction.actionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, filename));
                    } catch (Exception ex) {
                    }
                }
                return true;
            }
        });
    }
    /**
     * Pass this method an {@code ActionListener} equipped to
     * handle document events from the Finder.
     * Documents are registered with the Finder via the
     * CFBundleDocumentTypes dictionary in the application bundle's Info.plist.
     * <p>
     * The filename is passed as the {@code actionCommand}.
     */
    public static void setPrintFileHandler(ActionListener fileHandler) {
        setHandler(new OSXAdapter("handlePrintFile", fileHandler) {
            // Override OSXAdapter.callTarget to send information on the
            // file to be opened

            @Override
            public boolean callTarget(Object appleEvent) {
                if (appleEvent != null) {
                    try {
                        Method getFilenameMethod = appleEvent.getClass().getDeclaredMethod("getFilename", (Class[]) null);
                        String filename = (String) getFilenameMethod.invoke(appleEvent, (Object[]) null);
                        targetAction.actionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, filename));
                    } catch (Exception ex) {
                    }
                }
                return true;
            }
        });
    }

    /** 
     * {@code setHandler} creates a Proxy object from the passed
     * {@code OSXAdapter} and adds it as an {@code ApplicationListener}.
     */
    @SuppressWarnings("unchecked")
    public static void setHandler(OSXAdapter adapter) {
        try {
            Class applicationClass = Class.forName("com.apple.eawt.Application");
            if (macOSXApplication == null) {
                macOSXApplication = applicationClass.getConstructor((Class[]) null).newInstance((Object[]) null);
            }
            Class applicationListenerClass = Class.forName("com.apple.eawt.ApplicationListener");
            Method addListenerMethod = applicationClass.getDeclaredMethod("addApplicationListener", new Class[]{applicationListenerClass});
            // Create a proxy object around this handler that can be reflectively added as an Apple ApplicationListener
            Object osxAdapterProxy = Proxy.newProxyInstance(OSXAdapter.class.getClassLoader(), new Class[]{applicationListenerClass}, adapter);
            addListenerMethod.invoke(macOSXApplication, new Object[]{osxAdapterProxy});
        } catch (ClassNotFoundException cnfe) {
            System.err.println("This version of Mac OS X does not support the Apple EAWT.  ApplicationEvent handling has been disabled (" + cnfe + ")");
        } catch (Exception ex) {  // Likely a NoSuchMethodException or an IllegalAccessException loading/invoking eawt.Application methods
            System.err.println("Mac OS X Adapter could not talk to EAWT:");
            ex.printStackTrace();
        }
    }

    /** 
     * Each OSXAdapter has the name of the EAWT method it intends to listen for
     * (handleAbout, for example), the Object that will ultimately perform the
     * task, and the Method to be called on that Object.
     */
    protected OSXAdapter(String proxySignature, Object target, Method handler) {
        this.proxySignature = proxySignature;
        this.targetObject = target;
        this.targetMethod = handler;
    }

    /**
     * Each OSXAdapter has the name of the EAWT method it intends to listen for
     * (handleAbout, for example), the Object that will ultimately perform the
     * task, and the Method to be called on that Object.
     */
    protected OSXAdapter(String proxySignature, ActionListener handler) {
        this.proxySignature = proxySignature;
        this.targetAction = handler;
    }

    /** Override this method to perform any operations on the event
     * that comes with the various callbacks.
     * See setOpenFileHandler above for an example.
     */
    public boolean callTarget(Object appleEvent) throws InvocationTargetException, IllegalAccessException {
        if (targetAction != null) {
            targetAction.actionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, proxySignature));
            return true;
        } else {
            Object result = targetMethod.invoke(targetObject, (Object[]) null);
            if (result == null) {
                return true;
            }
            return Boolean.valueOf(result.toString()).booleanValue();
        }
    }

    /**
     * InvocationHandler implementation.
     * This is the entry point for our proxy object; it is called every time an 
     * ApplicationListener method is invoked.
     */
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        if (isCorrectMethod(method, args)) {
            boolean handled = callTarget(args[0]);
            setApplicationEventHandled(args[0], handled);
        }
        // All of the ApplicationListener methods are void;
        // return null regardless of what happens
        return null;
    }

    /**
     * Compare the method that was called to the intended method when the
     * OSXAdapter instance was created (e.g. handleAbout, handleQuit,
     * handleOpenFile, etc.).
     */
    protected boolean isCorrectMethod(Method method, Object[] args) {
        return (proxySignature.equals(method.getName()) && args.length == 1);
    }

    /** 
     * It is important to mark the ApplicationEvent as handled and cancel the
     * default behavior.
     * This method checks for a boolean result from the proxy method and sets 
     * the event accordingly.
     */
    protected void setApplicationEventHandled(Object event, boolean handled) {
        if (event != null) {
            try {
                Method setHandledMethod = event.getClass().getDeclaredMethod("setHandled", new Class[]{boolean.class});
                // If the target method returns a boolean, use that as a hint
                setHandledMethod.invoke(event, new Object[]{Boolean.valueOf(handled)});
            } catch (Exception ex) {
                System.err.println("OSXAdapter was unable to handle an ApplicationEvent: " + event);
                ex.printStackTrace();
            }
        }
    }
}
